Blue print machine



Jan. 3, 1932'. H. J. BRUNK BLUE PRINT MACHINE Filed April 5, 1930 2 Sheets-Sheet 1 ZjZZzrQZd J 731%2/0,

Jan; 5, 1932. H. J.'BRUNK 1,839,642

BLUE PRINT MACHINE Filed April 5, 1930 2 Sheets-Sheet 2 H1 Patented Jail; 5,1932

UNITED 'QSVTATE'S.

"PATENT OFFICE HAROLD J. BRUNK, OF CHICAGO, IIJLINOIS, ASSIGNOR TO F. PEASE COMPANY, A

CORPORATION OF DELAWARE BLUE PRINT MACHINE Application filed April 5, 1930. Serial No. 441,957.

Thisinvention relates to improvements in blue print machines and the like.

-One object of the invention is to provide a blue print machine, or machine of like character, in which the light from the light source is'concentrated upon a relatively small area lengthwise of the light sensitive paper during the printing operation, the concentration of light permitting and compensating for a shorter exposure of the paper to the light,

whereby certain advantages in the construction and operation of the machine are effected.

v In certain types of commercial blue printing machines now in use, an endless belt is employed for conveying the negatives and sensitive paper against a curved glass plate which is exposed to the source of light, usually a battery of arc lamps. The

exposure of the paper takes place as the paper and negatives are moved b the belt along the surface of the glass, an since the light from the lamps is more or less diffused, a relatively large plate of glass is required in order to expose the paper adequately to the light. By the present improve-' ments, the light is condensed by lenses and concentrated on a relatively small area lengthwise whereby a shorter plate may be so used which not only lessens the resistance offered to the movement of the paper and tracing, but permits quicker printing and also enables a more compact structure, of equal or greater efiiciency, to be provided.

Another object of the-invention is to provide mechanism whereby the light passing through the condensing lenses can be distributed over the entire exposable area of the paper in' such manner as to insure uniform exposure of the paper to the light during the operation of the machine.

Certain dilficulties arise in the use of are lamps due to overheating, to control which I artificial ventilation has been made use of -15 heretofore. A further object of the present invention is tominimize the objectionable heat by providing double walled reflectors for the arc lamps and circulating a cooling liquid therethrough.

An additional object is to support the lenses in a double walled or hollow support or frame and circulate a cooling liquid therethrough. In the accompanying drawings, Fig. 1 is a partial side elevation of a blue print machine embodying the present improvements, certain parts being shown in section.

Fig. 2 is a top plan view of a form of power take off mechanism for reciprocating the lenses, portions of the machine being omitted.

Fig. 3 is an elevation of the mechanism shown in Fig. 2.

Fig. 4 is an elevation on a small scale, of the preferred form of lens mounting.

Figs. 5 and 6 are views on .a small scale illustrating modified lens mountings.

In the drawings, 10 is a frame of a blue print machine carrying transverse rollers 11, 12 and 13, one of which, such as 13, being a power roller which actuates the endless belt or conveyor 14. One run of the belt 14 normally presses against the glass plate 15, which is suitably mounted in supports 16 or the like.

A row or battery of are lightsyincandescent lamps or other source of light indicated generally by the numeral 17, is arranged transversely of the machine, as shown, for providing the necessary light for exposing the light sensitive material such as blue print, white print, or other paper which is fed, together with the superimposed negative, between the belt 14 and the plate 15. The negative and sensitive paper are held by the belt against the rear face of the plate 15 and carried by the belt upwardly through the printing zone, and are removed at the top by discharging into a tray, or they may be carried by other mechanism, not shown, to a washing machine or the like. The lamps 17 are mounted on a suitable support 18, preferably in inclined position, in the embodiment herein shown.

- In commercial machines as at present gener- 15 which lies in the printing zone. The lower end of plate 15 is suitably curved as shown to permit the prints and negatives to enter readily between the plate and the conveyor 14:.

In order to use a shorter glass plate and thus reduce the friction of the belt on said glass and also to provide a more compact machine, a number of lenses 19 of suitable form are positioned one in front of each lamp 17. To permit the light concentration area of each lamp to overlap the corresponding area of adjacent lamps, and provide a uniform exposure throughout the width of the printing zone, means are provided for causing a relative back and forth movement of said lamps and lenses. In the preferred form the lamps are stationary and the lenses move back and forth in their own planes. For this purpose the lenses, as hereinafter explained, are carried on an inverted channel-shaped slide 20, supported by a transverse bar 21, which is secured by any desired means to the frame or other supporting part of the machine. A power take-off mechanism is provided, preferably in connection with the power drum 13, for effecting the reciprocation of said lenses and may consist of the cam 22 secured eccentrically to the shaft 23 of the drum 13. A reciprocating collar 24 is actuated by the cam 22 and is guided by suitable bearings 25. The collar has an extension or rack bar 26 the teeth of which mesh with the gear 27 carried on the shaft 28 which has at its upper end a slotted link 29 receiving a pin 30 mounted in the slide 20. It will be seen that as the shaft 23 rotates, rack bar 26 will be reciprocated, which movement will be transferred to the slide 20 by means of a shaft 28, arm 29 and pin 30.

The preferred form of lens support is a hollow frame 31 mounted on the slide 20 (Figs. 1 and t) and has openings therein to receive the lenses. Said frame is preferably made of heat conducting material, such as copper, and water or other cooling liquid is circulated through it, the connected hose lengths 32 being flexible and not interfering with the reciprocating movement.

In the modified form of lens supports shown in Fig. 3 where water cooling is dispensed with, lenses are mounted in circular frames 33 secured to the slide 20. The dotted line positions illustrate the range of movement.

A suitable parabolic reflector 34 is provided for each lamp 17 and directs the light against the corresponding lens 19, which in turn concentrates the light upon the plate 15, or the printing paper at the rear thereof, thus enabling the use of a shorter plate and a shorter period of exposure of the paper.

Said reflectors are preferably double walled structures as shown in Fig. 1 and are cooled by circulating liquid supplied from hose connections 35 and passing olf at the top through other connections 36.

In Figs. 5 and 6 further modifications of the lens mountings are shown diagrammatically. Ii Fig. 5 the lens 37 is shown posiuniformly exposed to the light.

I have shown and described certain features of my improvements for the purpose of illustration, but I do not wish to be restricted specifically to the details thereof, except as so limited by the appended claims.

What I claim is:

1. In a machine of the class described, a source of light, means for conveying a sheet of light sensitive material past said source, a lens for continuously concentrating the light from said source on said. sheet, and means for causing a to and fro movement of said lens in a direction transverse with respect to the travel of said sheet.

2. In a machine of the class described, a source of light, means for conveying a sheet of light sensitive material past said source, a plurality of condensing lenses between said sheet and source for concentrating the light therefrom upon said sheet, and means for moving said lenses to effect an overlapping of the light concentration area of each with the area of the adjacent lens to provide a relatively narrow exposure zone of uniform light intensity extending transversely of the direction of travel of said sheet.

3. In a machine of the class described, a transparent plate, means for conveying sensitized material past the same, an arc lamp mounted to pass light rays through said plate to said sensitized material, a hollow frame having openings therethrough, lenses in said openings in the path of said light rays, and means for conducting a cooling liquid to said hollow frame.

4. The combination with a blue print ma 5. The combination with a blue print machine comprising a battery of lamps, a transarent plate spaced therefrom, and an endess conveyor for carrying a sheet of light sensitive material and superimposed negative along the rear wall of said plate in exposablerelation with respect to said lamps, of a plurality of condensing lenses, one positioned between each lamp and said plate for concentrating the light upon said material, a slide supporting said lenses, and means for reciprocating said slide transversely of the direction of travel of said material for efiecting the overlapping of the light concentration areas of adjacent lenses.

6. In a blue print machine, the combination of a transparent plate, an endless conveyor, one run of which is adapted to press a sheet of light sensitive material and superimposed negative against one side of said plate and convey the same along the plate, rotatable drums over which said conveyor passes, a plurality of lamps positioned at the opposite side of said plate, condensing lenses, one p0- sitioned between each lamp and said plate for concentrating light upon said materlal, a slide member supporting said lenses, and power take off means operatively associated with one of said drums for reciprocating said slide member to eifect the overlapping of the light concentration areas of adjacent lenses.

7. In a blue print machine, the combination of a transparent plate, an endless conveyor, one run of which is adapted to press a sheet of light sensitive material and superimposed negative against one side of said plate and convey the same along the plate, rotatable drums over which said conveyor passes, a plurality of lamps positioned at the opposite side of said plate, condensing lenses,one positioned between each lamp and said plate for concentrating light upon said material, a slide member supporting said lenses, and power take of! means operatively associated with one of said drums for reciprocating said slide member to effect the overlapping of the light concentration areas of adjacent lenses, said power take off mechanism comprising a cam upon the shaft of said drum, a reciprocable rack bar operated by said cam and a shaft geared to said rack barand linked to said slide member.

8. In a machine ofthe class described, a source of light, means for conveying a sheet of light sensitive material past said source, a lens for continuouslyconcentratin light from said source in a beam u on sai material, and means for effecting limited relative movement between said lens and said light source for shifting said beam ,to and fro in a direction transverse with respect to the travel of said material.

In testimony whereof, I have subscribed my name.

HAROLD J. BR'UNK. 

